Equivalent. Alternative designs, materials, or methods that you can demonstrate will provide an equal or greater degree of safety for employees than the method or item specified in the standard.

Failure. Load refusal, breakage, or separation of component parts. Load refusal is the point where the structural members lose their ability to carry the loads.

Handrail. A rail used to provide employees with a handhold for support.

Lower levels. Those areas to which an employee can fall from a stairway or ladder. Such areas include ground levels, floors, roofs, ramps, runways, excavations, pits, tanks, material, water, equipment, and similar surfaces. It does not include the surface from which the employee falls.

Nosing. That portion of a tread projecting beyond the face of the riser immediately below.

Platform. A walking/working surface for persons, elevated above the surrounding floor or ground.

Point of access. All areas used by employees for work-related passage from one area or level to another. Such open areas include doorways, passageways, stairway openings, studded walls, and various other permanent or temporary openings used for such travel.

Riser height. The vertical distance from the top of a tread to the top of the next higher tread or platform/landing or the distance from the top of a platform/landing to the top of the next higher tread or platform/landing.

Spiral stairway. A series of steps attached to a vertical pole and progressing upward in a winding fashion within a cylindrical space.

Stair rail system. A vertical barrier erected along the unprotected sides and edges of a stairway to prevent employees from falling to lower levels. The top surface of a stair rail system may also be a "handrail."

Tread depth. The horizontal distance from front to back of a tread (excluding nosing, if any).

Unprotected sides and edges. Any side or edge (except at entrances to points of access) of a stairway where there is no stair rail system or wall 36 inches (.9 m) or more in height, and any side or edge (except at entrances to points of access) of a stairway landing, or ladder platform where there is no wall or guardrail system 39 inches (1 m) or more in height.

PDFWAC 296-155-47501

Definitions applicable to this part.